Travel Time Reliability Based Work Zone Scheduling.
详细信息
文摘
The continued deterioration of highway infrastructure in the US has resulted in increased number,duration,and scope of work zone projects. Transportation agencies are facing great challenges to schedule and manage work zones efficiently and economically. To improve the decision making process,in the past decades,several models have been developed to determine an optimal single work zone project schedule and operational strategy. Existing work zone scheduling models usually assume fixed average traffic impact given a designed work zone schedule. Recently,the incorporation of travel time reliability (TTR) in evaluating highway facility and traffic improvement projects has drawn increased attention. In comparison to traditional average travel time based methods,it considers the full distribution of travel time under a large number of traffic scenarios such as demand fluctuations,incidents,weather,etc. rather than an average value thus provide more comprehensive insights on the potential traffic impact of a highway improvement plan and new transportation facilities. However,the existing Highway Capacity Manual (HCM) toolbox of evaluating travel time reliability is complex and inefficient to be integrated into the optimization framework of work zone scheduling problem. In this study,we develop simplified methods that identify and model the work zone impact on travel time and travel time reliability to provide evaluation input for the work zone scheduling problem. Combined with the work zone cost such as maintenance cost,the user cost,and additional accident cost,a new work zone schedule model is proposed that incorporates travel time reliability measures. A genetic algorithm is used to solve this combinational optimization problem. Numeric examples are carried out to demonstrate the applicability and effectiveness of the developed model. Sensitivity analysis about maximum project duration and value of reliability is also conducted. The results indicate that this TTR based work zone scheduling is effective and promising.